1. Field of the Invention
The present invention relates to a method for making gravel filters in oil well bores, particularly in those oil well bores where there are water veins near oil producing formations.
2. Description of the Related Art
Some producing formations tapped by oil well installations have sandy characteristics that require the creation of gravel filters adjacent to the producing formation. The present methods typically gun the casing to make holes that connect the producing tube with a gravel filter that is defined by the inner surface of the well bore and the outer surface of the casing. This results in a very limited and thin gravel filter that is susceptible to getting clogged thereby frequently interrupting the operation of the well. The method is also not very precise.
Several methods for making gravel filters in oil well bores have been used in the past. None of them, however, have the flexibility and precision, nor the effectiveness (from its larger size), of the present method. Additionally, this method can be used in new and old oil wells, including those where the gun method was used. The precision characteristics of the present method are quite desirable in oil wells with water veins in relative proximity to the oil producing formation.
Applicant believes that the closest reference corresponds to U.S. Pat. No. 3,850,246 issued to Despujols for a gravel packing method and apparatus.
However, it differs from the present invention because the gravel is delivered through and out of the screen, necessitating additional sealing members 48, 50, and 52. Also, the diameter size of the gravel is severely limited by the constraints of the passages through which the gravel is passed.
Other documents describing the closest subject matter provide for a number of more or less complicated features that fail to solve the problem in an efficient and economical way. None of these patents suggest the novel features of the present invention.